// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/audio/alsa/alsa_util.h"

#include <stddef.h>

#include "base/logging.h"
#include "media/audio/alsa/alsa_wrapper.h"

namespace alsa_util {

static snd_pcm_t* OpenDevice(media::AlsaWrapper* wrapper,
    const char* device_name,
    snd_pcm_stream_t type,
    int channels,
    int sample_rate,
    snd_pcm_format_t pcm_format,
    int latency_us)
{
    snd_pcm_t* handle = NULL;
    int error = wrapper->PcmOpen(&handle, device_name, type, SND_PCM_NONBLOCK);
    if (error < 0) {
        LOG(WARNING) << "PcmOpen: " << device_name << ","
                     << wrapper->StrError(error);
        return NULL;
    }

    error = wrapper->PcmSetParams(handle, pcm_format,
        SND_PCM_ACCESS_RW_INTERLEAVED, channels,
        sample_rate, 1, latency_us);
    if (error < 0) {
        LOG(WARNING) << "PcmSetParams: " << device_name << ", "
                     << wrapper->StrError(error) << " - Format: " << pcm_format
                     << " Channels: " << channels << " Latency: " << latency_us;
        if (alsa_util::CloseDevice(wrapper, handle) < 0) {
            // TODO(ajwong): Retry on certain errors?
            LOG(WARNING) << "Unable to close audio device. Leaking handle.";
        }
        return NULL;
    }

    return handle;
}

static std::string DeviceNameToControlName(const std::string& device_name)
{
    const char kMixerPrefix[] = "hw";
    std::string control_name;
    size_t pos1 = device_name.find(':');
    if (pos1 == std::string::npos) {
        control_name = device_name;
    } else {
        // Examples:
        // deviceName: "front:CARD=Intel,DEV=0", controlName: "hw:CARD=Intel".
        // deviceName: "default:CARD=Intel", controlName: "CARD=Intel".
        size_t pos2 = device_name.find(',');
        control_name = (pos2 == std::string::npos) ? device_name.substr(pos1) : kMixerPrefix + device_name.substr(pos1, pos2 - pos1);
    }

    return control_name;
}

snd_pcm_format_t BitsToFormat(int bits_per_sample)
{
    switch (bits_per_sample) {
    case 8:
        return SND_PCM_FORMAT_U8;

    case 16:
        return SND_PCM_FORMAT_S16;

    case 24:
        return SND_PCM_FORMAT_S24;

    case 32:
        return SND_PCM_FORMAT_S32;

    default:
        return SND_PCM_FORMAT_UNKNOWN;
    }
}

int CloseDevice(media::AlsaWrapper* wrapper, snd_pcm_t* handle)
{
    std::string device_name = wrapper->PcmName(handle);
    int error = wrapper->PcmClose(handle);
    if (error < 0) {
        LOG(ERROR) << "PcmClose: " << device_name << ", "
                   << wrapper->StrError(error);
    }

    return error;
}

snd_pcm_t* OpenCaptureDevice(media::AlsaWrapper* wrapper,
    const char* device_name,
    int channels,
    int sample_rate,
    snd_pcm_format_t pcm_format,
    int latency_us)
{
    return OpenDevice(wrapper, device_name, SND_PCM_STREAM_CAPTURE, channels,
        sample_rate, pcm_format, latency_us);
}

snd_pcm_t* OpenPlaybackDevice(media::AlsaWrapper* wrapper,
    const char* device_name,
    int channels,
    int sample_rate,
    snd_pcm_format_t pcm_format,
    int latency_us)
{
    return OpenDevice(wrapper, device_name, SND_PCM_STREAM_PLAYBACK, channels,
        sample_rate, pcm_format, latency_us);
}

snd_mixer_t* OpenMixer(media::AlsaWrapper* wrapper,
    const std::string& device_name)
{
    snd_mixer_t* mixer = NULL;

    int error = wrapper->MixerOpen(&mixer, 0);
    if (error < 0) {
        LOG(ERROR) << "MixerOpen: " << device_name << ", "
                   << wrapper->StrError(error);
        return NULL;
    }

    std::string control_name = DeviceNameToControlName(device_name);
    error = wrapper->MixerAttach(mixer, control_name.c_str());
    if (error < 0) {
        LOG(ERROR) << "MixerAttach, " << control_name << ", "
                   << wrapper->StrError(error);
        alsa_util::CloseMixer(wrapper, mixer, device_name);
        return NULL;
    }

    error = wrapper->MixerElementRegister(mixer, NULL, NULL);
    if (error < 0) {
        LOG(ERROR) << "MixerElementRegister: " << control_name << ", "
                   << wrapper->StrError(error);
        alsa_util::CloseMixer(wrapper, mixer, device_name);
        return NULL;
    }

    return mixer;
}

void CloseMixer(media::AlsaWrapper* wrapper, snd_mixer_t* mixer,
    const std::string& device_name)
{
    if (!mixer)
        return;

    wrapper->MixerFree(mixer);

    int error = 0;
    if (!device_name.empty()) {
        std::string control_name = DeviceNameToControlName(device_name);
        error = wrapper->MixerDetach(mixer, control_name.c_str());
        if (error < 0) {
            LOG(WARNING) << "MixerDetach: " << control_name << ", "
                         << wrapper->StrError(error);
        }
    }

    error = wrapper->MixerClose(mixer);
    if (error < 0) {
        LOG(WARNING) << "MixerClose: " << wrapper->StrError(error);
    }
}

snd_mixer_elem_t* LoadCaptureMixerElement(media::AlsaWrapper* wrapper,
    snd_mixer_t* mixer)
{
    if (!mixer)
        return NULL;

    int error = wrapper->MixerLoad(mixer);
    if (error < 0) {
        LOG(ERROR) << "MixerLoad: " << wrapper->StrError(error);
        return NULL;
    }

    snd_mixer_elem_t* elem = NULL;
    snd_mixer_elem_t* mic_elem = NULL;
    const char kCaptureElemName[] = "Capture";
    const char kMicElemName[] = "Mic";
    for (elem = wrapper->MixerFirstElem(mixer);
         elem;
         elem = wrapper->MixerNextElem(elem)) {
        if (wrapper->MixerSelemIsActive(elem)) {
            const char* elem_name = wrapper->MixerSelemName(elem);
            if (strcmp(elem_name, kCaptureElemName) == 0)
                return elem;
            else if (strcmp(elem_name, kMicElemName) == 0)
                mic_elem = elem;
        }
    }

    // Did not find any Capture handle, use the Mic handle.
    return mic_elem;
}

} // namespace alsa_util
